First observation of mutual energy transfer of Mn4+–Er3+via different excitation in Gd2ZnTiO6:Mn4+/Er3+phosphors

Mutual sensitized luminescence of Mn⁴⁺–Er³⁺are realizedviadifferent excitation in Gd₂ZnTiO₆:Mn⁴⁺/Er³⁺phosphors. The upconversion from Er³⁺to Mn⁴⁺is first observed under 980 nm excitation. The downshift from Mn⁴⁺to Er³⁺is observed under 335 nm.